The information, said to be connected to an Islamic State plot using laptops onboard passenger aircraft, was given to the US by an ally who did not give consent for it to be shared with Russia.

Although Trump is not accused of divulging a specific source, current and former US officials told the Washington Post, which broke the story, that the disclosures jeopardised a critical source of intelligence on Isis.

The president’s tweets did not specify whether the information he shared with the Russians was classified. Nor did he address the accusations that the information was given by an ally who did not consent for it to be shared with Russia and that the disclosure jeopardised a source.

Trump’s national security adviser insisted that the revelations were “wholly appropriate” and amounted to a routine sharing of information. HR McMaster added that none of the US officials present at the meeting last week “felt in any way that that conversation was inappropriate.”

The secretary of state, Rex Tillerson, said “the nature of specific threats were discussed, but they did not discuss sources, methods or military operations”.

How have Democrats and Republicans reacted?

Bob Corker, the Republican chair of the Senate committee on foreign relations, said that if true, the story was “very, very troubling”. “The White House has got to do something soon to bring itself under control and in order. It’s got to happen,” he added. “Obviously, they’re in a downward spiral right now, and they’ve got to figure out a way to come to grips [with] all that’s happening.”

Senior Republican senator John McCain told CNN that “if it’s true, it’s obviously disturbing”. But he cautioned: “Let’s wait and see what this was all about first.”

A spokesman for Paul Ryan, Republican speaker of the House of Representatives, said: “We have no way to know what was said, but protecting our nation’s secrets is paramount.”

He said the speaker was hoping for a full explanation.

The Democratic National Committee said in a statement: “If Trump weren’t president, his dangerous disclosure to Russia could end with him in handcuffs.”

Mark Warner, the senior Democrat on the Senate intelligence committee, tweeted: “If true, this is a slap in the face to the intel community. Risking sources and methods is inexcusable, particularly with the Russians.”

Democratic Whip Dick Durbin said the president’s reported actions were “dangerous and reckless”.

Controversy over the timing of the meeting was heightened by the fact that US reporters were barred access to the Oval Office at the same time as Russian state media was admitted. The Kremlin-backed Itar-Tass subsequently shared a number of photographs of Trump entertaining Lavrov and Kislyak.

What are the risks of Trump’s actions to intelligence-sharing?

The story plays to existing fears among some allies about the president’s close relationship with Moscow. They could react by reducing intelligence-sharing, with a potentially devastating impact on security. The biggest impact is likely to be felt in counter-terrorism, where attacks can be planned on one side of the globe and executed on another.

Richard Nephew, a former National Security Council and state department official now at Columbia University, said: “People may die, including American citizens, if fear over Trump leaking leads to refusal to share sensitive information in the future.” He added: “I think it may be impossible to overstate how bad and dangerous this might turn out to be.”